Enhanced treatment of azo dyes in wastewater using heat-activated persulfate with micro-nano bubble aeration

Abstract

Azo dyes-containing wastewater can lead to environmental issues and pose threats to public health. The efficient degradation of azo dyes with novel and potent techniques, remains a challenge. This study presented an innovative utilization of micro-nano bubble aeration technology to improve the treatment of Rhodamine B through heat-activated persulfate oxidation. Through single factor experiments, the impacts of persulfate concentration, temperature, initial Rhodamine B concentration, and pH values were systematically explored on the degradation of Rhodamine B in heat-activated persulfate oxidation. The removal rate of Rhodamine B was 94.53% optimized by Response surface optimization method. The reaction rate was in the range of 0.0109–0.0528 min−1, governed by pseudo-first-order kinetics. By applying the Arrhenius equation, the activation energy was determined to be 14.06 KJmol−1. Furthermore, properties of micro-nano bubbles and their synergistic coefficient were investigated in heat-activated persulfate oxidation. Quenching tests revealed the predominance of sulfate radicals, and full wavelength scanning facilitated an in-depth investigation of the reaction mechanism. Additionally, a proposed electron shell structure elucidated the decomposition process of Rhodamine B. Therefore, the implementation of micro-nano bubble aeration technology based on heat-activated persulfate oxidation, held the promise as an efficient and effective approach for the treatment of printing and dyeing wastewater.